ML24331A137
| ML24331A137 | |
| Person / Time | |
|---|---|
| Site: | 07109186 |
| Issue date: | 12/27/2024 |
| From: | Storage and Transportation Licensing Branch |
| To: | |
| Shared Package | |
| ML24331A134 | List: |
| References | |
| EPID L-2024-LLA-0081 | |
| Download: ML24331A137 (1) | |
Text
Enclosure 2 UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 SAFETY EVALUATION REPORT Docket No. 71-9186 Model No. S-6213 Power Unit Shipping Container Certificate of Compliance No. 9186 Revision No. 21
SUMMARY
By letter dated June 11, 2024 (Agencywide Documents Access and Management System Accession No. ML24166A230), the U.S. Department of Energy, Division of Naval Reactors submitted an application for review and concurrence of the S-6213 power unit shipping container (PUSC) safety analysis report for packaging (SARP), revision original (revision 0),
which evaluates adding the S1B power unit as new authorized contents for the S-6213 PUSC.
The U.S. Nuclear Regulatory Commission (NRC) staff (the staff) reviewed the application using the guidance in NUREG-2216, Standard Review Plan for Transportation Packages for Spent Fuel and Radioactive Material." Based on the statements and representations in the application, the staff agrees that these changes do not affect the ability of the package to meet the requirements of Title 10 of the Code of Federal Regulations (10 CFR) Part 71. The staff concludes that the S1B power unit can be added as new authorized contents for the S-6213 PUSC.
1.0 GENERAL INFORMATION 1.1 Packaging The S-6213 PUSC is designed for shipment of a power unit complete with control rods and control rod drive mechanisms installed. There are three versions of the PUSC which differ by primary material of construction. The Model 1 S-6213 PUSC consists of a carbon steel cylindrical shell approximately 9 1/4 feet in outside diameter by 39 1/2 feet (ft.) long, including hemispherical steel end impact limiters, with 10 3/4 ft. outside diameter central flanges joining the barrel and cover halves. The Model 2 and Model 3 S-6213 PUSCs are of the same design as the Model 1, except that the primary container materials are HY-80 steel and HSLA-100 steel, respectively. The S1B power unit can be shipped in either the Model 2 or Model 3 PUSC. An internal pressure cap and seal ring are attached to the PUSC barrel flange. A power unit is supported in the PUSC by a centrally located thick circular steel plate which is clamped between the central mating flanges of the PUSC and fastened by ninety-four, 2-inch (in.) diameter high strength studs. The upper and lower extremities of the power unit cantilever into the barrel and cover halves without additional support. A lifting and shipping ring and a flange adapter are installed in the container during shipment of the S1B power unit. The PUSC is shipped in the horizontal position on a support frame which is secured to a specially built flatbed rail car. The weight of the PUSC, including frame and contents, is approximately 366,700 pounds (lbs.) for shipment of the S1B power unit.
The staff reviewed the package description provided in the application. The staff determined that it adequately describes the package configuration. Therefore, the staff finds it acceptable.
2 1.2 Drawings The applicant provided all engineering drawings referenced in the SARP. The staff finds the drawings are acceptable because they contain sufficient information to evaluate the impact of the S1B power unit as new contents on the package performance.
1.3 Contents The applicant added the S1B power unit as a new authorized contents for the S-6213 PUSC.
1.4 Findings
Based on a review of the statements and representations in the application, the staff concludes that the package has been adequately described to meet the requirements of 10 CFR Part 71.
2.0 STRUCTURAL The applicant, Department of Energy, Division of Naval Reactors (DOE-NR), submitted an application for the S1B power unit in the S-6213 PUSC, which is a Type B spent fuel transportation package (Reference 1). The applicant submitted a SARP, Revision 0 (Original),
to the NRC for review and evaluation. The objective of the structural evaluations is to verify that the structural performance of the package meets the regulatory requirements of 10 CFR Part 71 (Reference 2).
2.1 Description of Structural Design 2.1.1 General The applicant provided the descriptions of the S1B power unit in the S-6213 PUSC (herein referred to as the S1B in the PUSC) in section 1.1, INTRODUCTION, section 1.2, PACKAGE DESCRIPTION, and section 2.1, DESCRIPTION OF STRUCTURAL DESIGN, of the SARP.
The principal structural components of the S1B in the PUSC are the PUSC assembly, fuel cell assemblies, control rod assemblies, control drive mechanism (CDM) assemblies, core basket assembly, closure head assembly, flange adapter, and lifting and shipping ring. The detailed descriptions of the assemblies and individual components are documented in the SARP.
The applicant used a combination of closed-form solutions, hand calculations, and finite element (FE) analyses to evaluate the structural performance of the S1B in the PUSC under normal conditions of transport (NCT) and hypothetical accident conditions (HAC). The applicant established the design criteria based on the safety function and consequence of failure of each component. Some of the main design criteria are:
Allowable Stresses and Strains: Allowable stress and strain limits are summarized in two tables in section 2.1.2.1, Allowable Stresses and Strain Limits, of the SARP. The 1st table in section 2.1.2.1 presents the limits for the PUSC and adaptive hardware, and the 2nd table presents the limits for the S1B power unit components. The S1B power unit components are designed based on the component minimum material yield strength under NCT and their minimum ultimate strength or a conservative plastic limit under HAC, except for the fueled region of the fuel clusters that are based on the minimum yield strength under HAC.
Load Combinations: Applicable load combinations are summarized in table 2.6-1 in section 2.6 and table 2.7-1 in section 2.7 of the SARP. These loading configurations are in accordance with
3 Regulatory Guide (RG) 7.8, Load Combinations for the Structural Analysis of Shipping Casks for Radioactive Material (Reference 3).
2.1.2 Identification of Codes and Standards for Package Design The applicant provided the engineering design drawings in appendix 1.3.3, Engineering Drawings, of the SARP. These drawings provide detailed material requirements in support of component fabrication. Tables 2.2-1 through 2.2-4 provide the material specifications and properties used in the fabrication and examination of the package components.
The majority of the package components are fabricated, examined, and designed in accordance with the Naval Nuclear Propulsion Program (NNPP) requirements with military standard specifications and industry requirements (i.e., American Society of Mechanical Engineers
[ASME] Boiler and Pressure Vessel [B&PV] Code, American Society for Testing and Materials
[ASTM] Code, etc.).
The staff reviewed the structural design descriptions of the package and determined that the contents of the application satisfy the requirements of 10 CFR Section 71.31 and 10 CFR 71.33.
2.2 General Requirements for All Packages 2.2.1 Minimum Package Size As required in 10 CFR 71.43(a) the smallest overall dimension of a package may not be less than 4 in.
Appendix 1.3.3, Engineering Drawings, of the SARP documents that the smallest overall package dimension in length and diameter exceeds the minimum dimension requirement of 4 in.
specified in 10 CFR 71.43(a).
The staff determined that the application satisfies the regulatory requirements of 10 CFR 71.43(a).
2.2.2 Tamper-Indicating Feature As required in 10 CFR 71.43(b) the outside of a package must incorporate a feature, such as a seal, that is not readily breakable and that, while intact, would be evidence that the package has not been opened by unauthorized persons.
The staff reviewed the package descriptions and confirmed that security seals are provided at the closure joints. These security seals are shown in drawing F-425 of the SARP. The presence of the security seals indicates that the unauthorized opening of the package has not occurred.
This tamper-indication feature meets the requirements of 10 CFR 71.43(b).
The staff determined that the application satisfies the regulatory requirements of 10 CFR 71.43(b).
4 2.2.3 Positive Closure As required in 10 CFR 71.43(c) each package must include a containment system securely closed by a positive fastening device that cannot be opened unintentionally or by a pressure that may arise within the package.
The staff reviewed the PUSC package closure descriptions and confirmed that the positive closure of the openings through the containment system is accomplished by bolted closures, which are capable of withstanding pressures that may arise in the package and are also inaccessible and cannot be inadvertently moved to open the PUSC.
The staff determined that the application satisfies the regulatory requirements of 10 CFR 71.43(c).
2.2.4 Package Valve As required in 10 CFR 71.43(e) a package valve or other device, the failure of which would allow radioactive contents to escape, must be protected against unauthorized operation and, except for a pressure relief device, must be provided with an enclosure to retain any leakage.
The applicant stated in chapter 4, CONTAINMENT, of the SARP that the cladding containment boundary is not breached at any time. Additionally, the applicant demonstrated that the containment boundary is not breached under both NCT and HAC in chapter 2, STRUCTURAL EVALUATION. Based on these evaluations, the applicant concluded that there are no valves or other devices whose failure would allow radioactive material to escape, thereby, the S1B in the PUSC meets the requirements of 10 CFR 71.43(e). The staff reviewed the package descriptions and agreed that the S1B in the PUSC package does not have any valves or other devices on the containment boundary whose failure would allow for the escape of radioactive material.
Therefore, the staff found the applicants conclusion acceptable.
The staff determined that the application satisfies the regulatory requirements of 10 CFR 71.43(e).
2.3 Lifting and Tie-Down Standards for All Packages 2.3.1 Lifting Devices The applicant described the lifting devices of the package in section 2.5.1 of the SARP and provided a drawing of the lifting arrangement and loading diagram of the S1B in the PUSC in figure 2.5-1 of the SARP. The applicant calculated the forces acting on the lifting lugs under gravitational forces for the S1B in the PUSC and compared the results of the calculation with the results of the calculation for the S8G in the PUSC, which was previously reviewed and accepted by the staff (Reference 4). From the comparison study, the applicant found that the stresses of the S8G in the PUSC bound the stresses of the S1B in the PUSC. Based on this finding, the applicant concluded that the design of the lifting devices for the package are in compliance with the requirements of 10 CFR 71.45(a) since (i) the calculated stresses of the S1B in the PUSC package are bounded by the stresses of the S8G in the PUSC package, (ii) the lifting devices of the S1B in the PUSC package are similar to the lifting devices of the S8G in the PUSC package, and (iii) the lifting devices of the S8G in the PUSC package were previously reviewed and accepted by the staff. The staff reviewed the applicants statements and concluded that the rationale for the applicants conclusion is acceptable.
5 The staff determined that the application satisfies the regulatory requirements of 10 CFR 10 CFR 71.45(a).
2.3.2 Tie-Down Devices The applicant described the tie-down devices of the package in section 2.5.2 of the SARP. The applicant stated that the weight of the S1B in the PUSC package is less than the weight of the S6W in the PUSC package in Reference 5. The applicant concluded that the design of the tie-down devices for the package are in compliance with the requirements of 10 CFR 71.45(b) because (i) the weight of the S1B in the PUSC package is less than the weight of the S6W in the PUSC package, (ii) the tie-down devices of the S1B in the PUSC package are similar to the tie-down devices of the S6W in the PUSC package, and (iii) the tie-down devices of the S6W in the PUSC package were previously reviewed and accepted by the staff. The staff reviewed the applicants statements and concluded that the rationale for the applicants conclusion is acceptable.
The staff determined that the application satisfies the regulatory requirements of 10 CFR 71.45(b).
2.4 General Considerations for Structural Evaluation of Packaging The applicant performed structural analyses for the S1B in the PUSC under both NCT and HAC using the FE method with the computational modeling program, ABAQUS, which is a software application that can be used for both the modeling and analysis of structural components and assemblies. Physical testing was not done on the S1B in the PUSC package. However, the applicant stated that the ABAQUS FE program and the analysis techniques (i.e., computer model, analysis code, assumptions, boundary conditions, material model, etc.) employed for all structural analyses in the SARP have been extensively used and verified throughout the previous structural analyses within the NNPP.
The applicant created four FE models using the ABAQUS FE program to evaluate the S1B in the PUSC under NCT and HAC. The first model is a half-symmetry model used for the analysis of the NCT free drop as well as the HAC free drop conditions. This model consists of three major sub-assemblies, which are: (i) a core-independent subassembly of components representing the transportation packaging, (ii) a core-dependent subassembly representing the S1B power unit, and (iii) a set of core-dependent adaptive hardware that interfaces between the PUSC and the S1B power unit. This half-symmetry model defines a symmetry plane along the longitudinal axis of the transportation package and is normal to the unyielding surface. A more detailed description of the model is provided in section 2.12.8.1 of appendix 2.12.8, Finite Element Analysis (FEA) Model Descriptions, of the SARP.
From the half symmetry model, two additional models are developed that include the entire package (360-degree [°] models) in order to evaluate impacts that are not on the package symmetry plane. Therefore, 360° models are only used where the half-symmetry does not provide an appropriate representation of the package. Two 360° models of the S1B in the PUSC are used to analyze the 360-degree oblique drop model and the 360° support bracket model. A more detailed description of the model is provided in section 2.12.8.2 of appendix 2.12.8 of the SARP.
6 A third, 360°, model is developed from the 360° oblique drop model in order to evaluate a subsequent HAC puncture event with the damage accumulated from the HAC free drop. A more detailed description of the model is provided in section 2.12.8.3 of appendix 2.12.8 of the SARP.
A fourth, half symmetry, model is developed to assess the cover pressure cap and impact limiter fasteners for the NCT free drop by adding fasteners and creating holes in the associated cover, pressure cap, and impact limiter geometries. A more detailed description of the model is provided in section 2.12.8.4 of appendix 2.12.8 of the SARP.
The geometry and model data used in the ABAQUS FE models are summarized in tables 2.12.8.1 through 2.12.8.4 and figures 2.12.8.1 through 2.12.8.4 of the SARP.
The staff reviewed the model descriptions and technical information provided in the SARP and associated appendices for the package modeling and analyses. The staff concluded that the ABAQUS FE models are adequately developed to analyze the S1B in the PUSC under NCT and HAC.
The staff determined that the application satisfies the regulatory requirements of 10 CFR 71.41(a).
2.5 Normal Conditions of Transport The applicant evaluated the S1B in the PUSC for NCT heat, cold, reduced external pressure, increased external pressure, vibration and fatigue, water spray, free drop, corner drop, compression, and penetration as required by 10 CFR 71.71 and documented the evaluations in section 2.6 of the SARP.
2.5.1 Heat As required in 10 CFR Part 71.71(c)(1) the package be subjected to an ambient temperature of 100 degrees Fahrenheit (°F) in still air and insolation.
The applicant performed thermal analyses for the S1B in the PUSC package and presented the evaluation findings in chapter 3, THERMAL EVALUATION, of the SARP. The staffs detailed safety evaluations on the applicants thermal analyses are provided in section 3.0, THERMAL EVALUATION, of this safety evaluation report (SER). The applicant stated that since the S1B in the PUSC contains unirradiated fuel and does not generate heat, the thermal analyses performed for the S1B in the PUSC package were only subjected to hot environment conditions (ambient temperature of 100°F in still air and maximum insolation). The results of the thermal analyses are provided in chapter 3 of the SARP, and they are used to support various aspects of the structural evaluations.
Summary of Pressure and Temperatures: The applicant calculated the maximum internal pressure based on a temperature change between the minimum and maximum temperatures in the PUSC with the assumption that the PUSC pressure relief valves remain sealed. Section 2.12.2.3.1 of appendix 2.12.2 of the SARP provides the calculations. This calculated maximum internal pressure is used for the structural analyses of the SARP.
7 Differential Thermal Expansion: The applicant documented a differential thermal expansion of the PUSC components in section 2.12.2.1.1.3 of appendix 2.12.2 of the SARP and provided the calculated stresses in the PUSC components due to the thermal expansion in section 2.12.2.2.1 of appendix 2.12.2 of the SARP.
Stress Calculations and Comparison with Allowable Stresses: The applicant summarized the PUSC component stresses due to the differential thermal expansion in table 2.6-2 of the SARP.
The applicant compared the calculated stresses to the yield strength of the components and concluded that all PUSC components are acceptable because the calculated stresses are lower than the yield strength.
The staff reviewed the applicants evaluations and agreed with its conclusion that the PUSC components are acceptable because the calculated stresses are lower than the yield strength of the components.
The staff determined that the application satisfies the regulatory requirements of 10 CFR 71.71(c)(1).
2.5.2 Cold As required by 10 CFR 71.71(c)(2) the package be subjected to an ambient temperature of -
40°F in still air and shade.
Summary of Pressure and Temperatures: The applicant calculated the minimum internal pressure based on a temperature change between the minimum and maximum temperatures in the S1B and PUSC. Section 2.12.2.3.2 of appendix 2.12.2 of the SARP provides the calculations. This calculated minimum internal pressure is used for the structural analyses in the SARP.
Differential Thermal Contraction: The applicant considered a differential thermal contraction of the PUSC and S1B components in sections 2.12.2.1.1.3 and 2.12.2.1.2 of appendix 2.12.2 of the SARP and provided the calculated stresses in the components due to the thermal contraction.
Stress Calculations and Comparison with Allowable Stresses: The applicant provided the PUSC component stresses due to the differential thermal contraction in table 2.6-3 of the SARP. The applicant compared the calculated stresses to the yield strength of the components and concluded that the PUSC components are acceptable because the calculated stresses are lower than the yield strength of the components.
The staff reviewed the applicants evaluations and agreed with its conclusion that the PUSC components are acceptable because the calculated stresses are lower than the yield strength of the components.
The staff determined that the application satisfies the regulatory requirements of 10 CFR 71.71(c)(2).
2.5.3 Reduced External Pressure As required by 10 CFR Part 71.71(c)(3) the package be subjected to a reduced external pressure of 3.5 pounds per square inch absolute (psia).
8 The applicant evaluated the S1B in the PUSC subjected to a reduced external pressure of 3.5 psia. The applicant provided discussions for the effects of the reduced external pressure of 3.5 psia in section 2.6.3 of the SARP and section 2.12.2.3 of appendix 2.12.2. The applicant demonstrated that there is no effect on the components because the design pressures for the S1B and PUSC components bound the effects of a reduced external pressure of 3.5 psia. As a result, the applicant concluded that the reduced pressure as specified in 10 CFR 71.71(c)(3) will not affect the performance of the S1B in the PUSC package. The staff reviewed the applicants evaluations and agreed with its conclusion that there is no effect on the components of the S1B in the PUSC package by the reduced external pressure of 3.5 psia.
The staff determined that the application satisfies the regulatory requirements of 10 CFR 71.71(c)(3).
2.5.4 Increased External Pressure Pert 10 CFR71.71(c)(4), the package is required to be subjected to an external pressure of 20 psia.
The applicant evaluated the S1B in the PUSC subjected to an external pressure of 20 psia. The applicant provided discussions for the effects of the increased external pressure of 20 psia in section 2.6.4 of the SARP and section 2.12.2.3 of appendix 2.12.2. The applicant explained that there is no effect of the external pressure of 20 psia on the components because the design pressures for the S1B and PUSC components bound the external pressure of 20 psia. As a result, the applicant concluded that the increased pressure as specified in 10 CFR 71.71(c)(4) will not affect the performance of the S1B in the PUSC package. The staff reviewed the applicants evaluations and agreed with its conclusion that there is no effect on the components of the S1B in the PUSC package by the external pressure of 20 psia.
The staff determined that the application satisfies the regulatory requirements of 10 CFR 71.71(c)(4).
2.5.5 Vibration and Fatigue As required by 10 CFR 71.71(c)(5) the package be subjected to a vibration normally incident to transport.
Vibration load is discussed in section 2.6.5 of the SARP. The S1B in the PUSC is transported via rail, which may induce lower amplitude vibrations. The applicant stated that the worst-case maximum g-load induced by the railcar vibration is significantly smaller than 1 gram due to sufficient damping of the system. This finding is based on a previous NNPP experimental study on the S9G in the PUSC (Reference 6). In addition, the applicant stated that since the S1B in the PUSC is heavier than the S9G in the PUSC and the S1B power unit is designed to the various loads significantly greater than the vibration load, the S1B in the PUSC will not be affected by the vibration load under NCT.
The applicant also discussed fatigue cycles on the PUSC. The applicant stated that the PUSC have completed many loaded shipments and have been inspected. The results of the inspections have shown that there is no degradation due to a transportation-induced fatigue.
Based on this finding, the applicant concluded that the vibration due to normal transportation operation will not significantly induce cyclic or component fatigue in the existing PUSC
9 components. The staff reviewed the statements and concluded that the rationale for the conclusion is acceptable.
The staff determined that the application satisfies the regulatory requirements of 10 CFR 71.71(c)(5).
2.5.6 Water Spray As required by 10 CFR Part 71.71(c)(6), the package must be subjected to a water spray test that simulates exposure to rainfall of approximately 2 in. per hour (in./hr.) for at least 1 hr.
The water spray test is primarily intended for packaging relying on material that absorbs water and/or are softened by water. The applicant stated that the PUSC does not have any external surfaces that are absorbent or radioactive to water. The staff reviewed the statement and agreed that the water spray would not impair the PUSC package.
The staff determined that the application satisfies the regulatory requirements of 10 CFR 71.
71(c)(6).
2.5.7 Free Drop As required by 10 CFR 71.71(c)(7), the package must be subjected to a free drop through the distance specified in 10 CFR 71.71(c)(7) onto a flat, essentially unyielding, horizontal surface, striking the surface in a position for which maximum damage is expected.
The applicant performed a free drop analysis of the S1B in the PUSC. The applicant analyzed only a 1-ft. side drop because a 1-ft. drop in an impact orientation other than a side is not feasible due to the package size, shipped orientation, and method of shipment. The ABAQUS FE model was used to calculate the stresses of the components.
The results of the one-foot side drop analysis are documented in section 2.6.7 and section 2.12.2.6 of appendix 2.12.2 of the SARP. The drop analysis demonstrated that the S1B power unit and the PUSC remain essentially undamaged as a result of the 1-ft. side drop with two exceptions. First, a 1-ft. free drop resulted in small denting of the PUSC at the impact location, although this 1-ft. drop did not result in significant alteration of the package or its contents. The impacted region of the PUSC main flange and a small region of the surrounding areas were plastically deformed. All 93 main flange studs remained elastic except for one. Figures 2.12.2.6-1 and 2.12.2.6-2 in appendix 2.12.2 of the SARP show a distribution of plastic strains in the PUSC main flange area. Based on the results of the analysis and evaluations, the applicant concluded that the dent is negligible and there is no substantial reduction in package effectiveness. Second, the cover pressure cap screws may fail due to the 1-ft. free drop. This failure is primarily due to the transverse shear load that is applied by sliding the pressure cap.
The cover pressure cap remains clamped between the cover impact limiter flange and the upper over flange. Therefore, both the cover impact limiter and the cover pressure cap remain attached to the PUSC because all of the cover of impact limiter screws remain intact, and, as a result, it does not influence the package effectiveness in subsequent accident conditions of HAC. The applicant concluded that the free drop of the package through the distance specified in 10 CFR 71.71(c)(7) will not affect the performance of the S1B in the PUSC. The staff reviewed the applicants evaluations and agreed with the conclusion that the dent is very small and the results of the drop analysis show that the impact limiter screws remain intact; therefore, the 1-ft. side drop will not affect the performance of the S1B in the PUSC.
10 The staff determined that the application satisfies the regulatory requirements of 10 CFR 71.71(c)(7).
2.5.8 Corner Drop As required by 10 CFR 71.71(c)(8) the package must be subjected to a free drop onto each corner of the package in succession, or in the case of a cylindrical package onto each quarter of each rim, from a height of 1 ft. a flat, essentially unyielding, horizontal surface with a condition that this test applies only to fiberboard, wood, or fissile material rectangular packages not exceeding 110 lbs. and fiberboard, wood, or fissile material cylindrical packages not exceeding 220 lbs.
The applicant indicated that the corner drop test does not apply to the PUSC package since the package is not fabricated from fiberboard or wood and its weight is in excess of 220 lbs. As a result, 10 CFR 71.71(c)(8) is not applicable.
The staff determined that the regulatory requirements of 10 CFR 71.71(c)(8) are not applicable to the PUSC package.
2.5.9 Compression As required by 10 CFR 71.71(c)(9) the package weighing up to 11,000 lb. must be subjected, for a period of 24 hrs., to a compressive load applied uniformly to the top and bottom of the package in the position in which the package would normally be transported.
The applicant stated that the compression test does not apply to the PUSC package since its weight is in excess of 11,000 lbs. As a result, 10 CFR 71.71(c)(9) is not applicable.
The staff determined that the regulatory requirements of 10 CFR 71.71(c)(9) are not applicable to the S1B in the PUSC package.
2.5.10 Penetration As required by 10 CFR Part 71.71(c)(10) the impact of a hemispherical end of a vertical steel cylinder of 1.25 in. diameter and 13 lb. mass, dropped from a height of 40 in. onto the exposed surface of the package that is expected to be most vulnerable to puncture.
The applicant analyzed the PUSC package subjected to a penetration which consisted of dropping a 13 lb. steel bar of 1.25 in. diameter from a height of 40 in. onto the package. The calculated damage to the outer package is a very small localized dent, which is not sufficient in size to challenge the functional characteristics of the package. Based on this, the applicant concluded that the package meets the regulatory requirements of 10 CFR 71.71(c)(10) because the PUSC package is not susceptible to the 13 lb. bar. The staff reviewed the applicants evaluation and confirmed its finding of a very small dent. The staff agreed that the small dent would not cause the functional characteristics of the package.
The staff determined that the application satisfies the regulatory requirements of 10 CFR 71.71(c)(10).
11 2.6 Hypothetical Accident Conditions The applicant evaluated the S1B in the PUSC for free drop, crush, puncture, thermal, and water immersion under HAC as required by 10 CFR 71.73. The applicant evaluated the load combinations per RG 7.8 (Reference 3). The load combinations used for the HAC analyses are tabulated in table 2.71 of the SARP. Section 2.7 of the SARP provides a summary of the analyses and appendices 2.12.3 through 2.12.7 of the SARP provide the detailed analyses for the PUSC with S1B power unit and adaptive hardware under HAC.
2.6.1 Free Drop As required by 10 CFR 71.73(c)(1) a package needs to be demonstrated for structural adequacy by a free drop through a distance of 30 ft. onto a flat, unyielding, horizontal surface in a position for which maximum damage is expected.
The applicant analyzed three 30-ft. free drops: (i) 90o end drop, (ii) 0o side drop, and (iii) oblique drop for the S1B in the PUSC. The closed-form solutions and the ABAQUS FE analyses were used to calculate the stresses of the components under HAC. The FE analyses were used to either confirm the closed-form solutions or to analyze components with complex geometries and/or loadings for which there are no readily available closed-form solutions.
Sections 2.7.1.1 through 2.7.1.4 of the SARP summarize the S1B in the PUSC structural performance results for the individual orientations of the free drop. The package accelerations were established, and the g-load capacities of the component were determined, which are presented in table 2.12.3-1 in appendix 2.12.3. The applicant provided the following safety significant results of the analyses: (i) there was no significant deformation of the internal pressure cap and the pressure cap remained intact and retained within the PUSC, (ii) the power unit remained clamped between the PUSC cover and barrel, (iii) the PUSC barrel support bracket was considered to remain attached to the barrel shell and the closure head of the S1B power unit experienced no gross deformation, (iv) the maximum induced stress in the fuel cluster was found to be less than the yield strength of the material and all other components fuel module were shown not to fail in the free drops, (v) the CDM hold-down assembly was shown to remain elastic under the side and end drops, and (vi) in a side drop, the translating assembly, control rod assembly, and CDM latches yielded, but shown not to fail. Based on these results of the FE structural analyses, the applicant concluded that the S1B in the PUSC package is adequately designed and is safe under the HAC drops.
The staff reviewed the applicants structural analyses of the S1B in the PUSC package under the HAC free drop conditions. The staff found that the applicants FE model analyses were adequately performed, and the results of the analyses demonstrated that the HAC free drops will not result in any structural damage to the S1B in the PUSC package. Therefore, the staff concluded that that applicants evaluations for the S1B in the PUSC package under the HAC drops are acceptable.
The staff determined that the application satisfies the regulatory requirements of 10 CFR 71.73(c)(1).
2.6.2 Crush Per 10 CFR 71.73(c)(2), a dynamic crush test is required by positioning the specimen on a flat, essentially unyielding horizontal surface, so as to suffer maximum damage by the drop of a
12 1,100 lbs. mass from 30 ft. onto the specimen. However, the crush test is required only when the specimen has a mass not greater than 1,100 lbs.
The applicant stated that the crush test does not apply since the weight of the S1B in the PUSC is greater than 1,100 lbs. As a result, 10 CFR 71.73(c)(2) is not applicable. The staff agreed with the applicants conclusion.
The staff determined that the regulatory requirements of 10 CFR 71.73(c)(2) are not applicable to the S1B in the PUSC package.
2.6.3 Puncture Per 10 CFR Part 71.73(c)(3), a free drop of the specimen through a distance of 40 in. in a position for which maximum damage is expected, onto the upper end of a solid, vertical, cylindrical, mild steel bar mounted on an essentially unyielding, horizontal surface is required.
The bar must be 6 in. in diameter, with the top horizontal and its edge rounded to a radius of not more than 0.25 in., and of a length as to cause maximum damage to the package, but not less than 8 in. long. The long axis of the bar must be vertical.
The applicant performed the puncture drop analyses for the S1B in the PUSC in appendix 2.12.6 and summarized the analyses in section 2.7.3 of the SARP. Figures 2.12.6-2 through 2.12.6-11 of appendix 2.12.6 show different orientations and locations of the pin puncture to the PUSC. Figures 2.12.6-13 and 2.12.6-14 show the deformed shape of the near the outside of the internal pressure cap, while figure 2.12.6-15 shows the deformed shape of the compression tube. Table 2.12.6-1 summarizes the results of the analyses of the pin puncture for the S1B in the PUSC.
The results of the puncture analyses showed that a side drop onto a 6-in. diameter pin that makes contact with the lower barrel region may result in puncture of the PUSC wall.
Subsequently, the pin impacts the lower core basket. However, the pin did not puncture the core basket wall and there was no damage to the power unit fuel module. As a result, the containment boundary was maintained during the puncture accident. In addition, the analyses showed that the pin puncture accident will not cause control rod withdrawal beyond the distance assumed in the S1B power unit criticality evaluations in chapter 6, CRITICALITY EVALUATION, of the SARP or resulting alteration to the S1B fuel geometry. The staff reviewed the analyses results and evaluations and found that (i) the applicant demonstrated that the package function will not be impaired due to the puncture accident, and (ii) the applicants conclusion is acceptable because the containment boundary will be maintained during the puncture accident The staff determined that the application satisfies the regulatory requirements of 10 CFR 71.73(c)(3).
2.6.4 Thermal Per 10 CFR 71.73(c)(4), exposure of the package to an average flame temperature of at least 1,475°F for a period of 30 minutes (mins) is required.
The applicant performed thermal analyses of the S1B in the PUSC and presented the evaluation findings in chapter 3, THERMAL EVALUATION, of the SARP. The staffs detailed
13 safety evaluations on the applicants thermal analyses are provided in section 3.0, THERMAL EVALUATION, of this SER.
Summary of Pressure and Temperatures: The thermal analysis described in chapter 3 of the SARP provides the resultant conditions for the PUSC and its contents under the HAC fire accident, as summarized in table 2.7-2 of the SARP. The results of the analyses show that the O-rings that are located near the outside of the PUSC have the recommended maximum temperature of the O-rings, which is less than the HAC fire temperature. As a result, the O-rings may fail during the fire accident and PUSC internal pressure would be equalized with the atmosphere pressure. However, the applicant stated that this condition is acceptable because maintenance of the PUSC pressure is not required for the package safety.
Differential Thermal Contraction: The PUSC package components expand as the package temperature increases due to the HAC fire. However, the S1B power unit component design temperatures for in-plant operations are greater than the induced average package temperature due to the HAC fire as shown in table 2.7-2. Therefore, the stresses of the S1B power unit are acceptable when heated due to the HAC fire.
Stress Calculations and Comparison with Allowable Stresses: The applicant evaluated the PUSC main flange joint under the HAC fire in section 2.7.4 of the SARP. Stress in the main flange studs due to the thermal HAC was calculated. The result showed that the calculated stress is less than the yield stress of the material. Based on this result, the applicant concluded that the main flange studs will not yield to the HAC fire.
The staff reviewed the evaluations and found that the applicants conclusion is acceptable because the induced stress due to the HAC fire in the PUSC flange joint is lower than the yield strength of the material.
The staff determined that the application satisfies the regulatory requirements of 10 CFR 71.73(c)(4).
2.6.5 Immersion - Fissile Materials 10 CFR Part 71.73(c)(5) requires that for fissile material subject to 10 CFR 71.55, in those cases where water in-leakage has not been assumed for criticality analysis, it must be evaluated for immersion under a head of water of at least 3 ft. in the attitude for which maximum leakage is expected.
The applicant stated that the S1B in the PUSC package satisfies the regulatory requirements of 10 CFR 71.73(c)(5) because chapter 6, CRITICALTY EVALUATION, of the SARP provides a criticality evaluation that demonstrates subcriticality under the assumption that the PUSC allows in-leakage of water. The staff reviewed the statement and found it acceptable because it has demonstrated subcriticality with the assumption of water in-leakage in the PUSC. The staffs detailed reviews and safety evaluations on the applicants criticality evaluations are provided in section 6.0 of this SER.
The staff determined that the application satisfies the regulatory requirements of 10 CFR 71.73(c)(5).
14 2.6.6 Immersion - All Packages As required by 10 CFR 71.73(c)(6) a separate, undamaged specimen must be subjected to water pressure equivalent to immersion under a head of water of at least 50 ft. (equivalent pressure of 21.7 pounds per square inch gauge [psig]) for a period of 8 hrs.
The applicant evaluated the potential for leak-tight seals of the PUSC shell and the cover pressure cap under the external pressure in section 2.7.6 of the SARP. The evaluations are based on the calculations of the container pressure documented in section 2.12.2.3 of appendix 2.12.2. The calculations show that the cover pressure cap and the PUSC shell do not yield to an external water pressure of 21.7 psig. Additionally, the applicant documented the capacity of the barrel internal pressure cap in section 2.12.2.5 of appendix 2.12.2 and showed that the barrel pressure cap does not yield to an external water pressure of 21.7 psig. Based on the results of these analyses, the applicant concluded that the immersion requirement for all packages is met because the S1B in the PUSC remains leak-tight under a head of water of 50 ft. The staff reviewed the applicants analyses, results and evaluations for the immersion test and found them acceptable. The staff confirmed the applicants conclusion that the S1B in the PUSC package meets the requirements of 10 CFR 71.73(c)(6).
The staff determined that the application satisfies the regulatory requirements of 10 CFR 71.73(c)(6).
2.7 Air Transport Accident Conditions for Fissile Material The applicant stated that this test does not apply to the S1B in the PUSC package since the package will not be transported by air. The staff reviewed the statement and confirmed that the package will not be transported by air.
The staff determined that the regulatory requirements of 10 CFR 71.55(f) are not applicable to the S1B in the PUSC package.
2.8 Special Requirement for Type B Packages Containing More than 105 A2 As required by 10 CFR 71.61 a Type B package containing more than 105 A2 must be designed so that its undamaged containment system can withstand an external water pressure of 290 psi for a period of not less than 1 hr. without collapse, buckling, or in-leakage of water.
Table 2.7-4, Determination of A2 Value for S1B Power Unit, of the SARP shows that the S1B power unit contains an A2 value, which is less than the required limit of 105. Therefore, this special requirement for the Type B package is not applicable to the S1B in the PUSC. The staff reviewed the table and confirmed that the A2 value of the S1B power unit is less than the required limit of 105.
The staff determined that the regulatory requirements of 10 CFR 71.61 are not applicable to the S1B in the PUSC package.
2.9 Air Transport of Plutonium The applicant stated that the test does not apply to the S1B in the PUSC package since the package will not be transported by air. The staff reviewed the statement and confirmed that the package will not be transported by air.
15 The staff determined that the regulatory requirements of 10 CFR 71.64 and 71.74 are not applicable to the S1B in the PUSC package.
2.10 References 1.
Department of Energy (DOE), NR:RR:JHKampen G#C24-02642, S-6213 Shipping Container - Safety Analysis Report for Packaging to Support Shipment of S1B Power Unit; Request for Nuclear Regulatory Commission Review and Concurrence, June 11, 2024.
2.
10 CFR Part 71, Packaging and Transportation of Radioactive Material.
3.
U.S. Nuclear Regulatory Commission (NRC), Regulatory Guide 7.8, Revision 1, Load Combinations for the Structural Analysis of Shipping Casks for Radioactive Material, 1989.
4.
NPD-73-2011-UL, PUSC SARP - Safety Analysis for Shipping S8G Power Units in the S-6213 Container, Rev. 10, Knolls Atomic Power Laboratory for the U.S. DOE, May 16, 1977.
5.
WAPD-REO(C)-1566 - S6W Shipboard Power Unit in Model 2 S6213 Power Unit Shipping Container Safety Analysis Report for Packaging, Rev. 4, Bettis Atomic Power Laboratory (Transmitted by WAPD-REO(C)-1929, September 30, 1992.
6.
RSS-SC-NFE-00050 - S9G Power Unit in the S-6213 Power Unit Shipping Container Safety Analysis Report for Packaging Addendum, Rev. Original, Fluor Marine Propulsion, LLC for the DOE (Transmitted by RSS-SC-NFE-00075, December 15, 2022.
2.11 Evaluation Findings The staff reviewed and evaluated the applicants statements and representations in the application. Based on the review and evaluations, the staff concluded that the S1B in the PUSC package is adequately described, analyzed, and evaluated to demonstrate that its structural capability and integrity meet the regulatory requirements of 10 CFR Part 71.
3.0 THERMAL EVALUATION 3.1 Description of Thermal Design The PUSC package is a cylindrical container that includes impact limiters on each end. The package diameter is about 128 inches, and the overall length is approximately 37 feet. The PUSC is made with stainless steel sections bolted together. The joints are metal-to-metal contacts sealed with O-ring gaskets in grooves. Under normal operating conditions the O-rings maintain the initial container pressure. The container is shipped horizontally by rail car.
3.2 Summary of Temperatures According to the PUSC SARP thermal chapter, the maximum temperatures of the accessible surface of the package with its contents at hot normal conditions is less than the 185°F regulatory limit for exclusive use shipment described in 10 CFR 71.43(g). Predicted temperatures are provided in SARP section 3.1.3 for both Normal Conditions of Transport (NCT) and Hypothetical Accident Conditions (HAC).
16 3.3 Contents SARP chapter 3 states that the PUSC shipping package seeks approval of the S1B power unit.
There are no heat sources in the contents. The only heat source is solar heating on the exterior surface and the 100°F ambient temperature.
3.4 Summary of Maximum Pressures PUSC SARP thermal chapter provides package maximum calculated pressures at NCT and HAC in section 3.1.4.
3.5 Material Properties and Component Specifications For thermal properties, the approach described in SARP section 3.4 (HAC analysis) only consider the specific heat. The application provides specific heat for stainless steel at 70°F. No values are provided at higher temperatures since values at higher temperatures would tend to increase. Therefore, the applicants approach for using a single value is justified because the temperature rise during HAC would be generally lower than predicted in the SARP. Melting temperatures for relevant materials are provided in the SARP along with allowable temperature limits for all seals. Set points for relief valves are provided as well.
3.6 Thermal Evaluation Under Normal Conditions of Transport The calculation approach provided in the SARP to predict maximum temperature during NCT considers a steady state analysis of the container surface temperature. The approach considers surface area to be exposed to solar heating and cooled by radiation and convection. The heat balance in the exposed surface area is solved for the temperature of the surface. SARP analysis during NCT shows that the maximum temperatures are acceptable for the shipment of the S1B power unit. The accessible exterior surface temperature of the PUSC will not exceed 185°F limit for an exclusive use shipment. In addition, the maximum temperatures and internal pressures of the package will not exceed the limits established in the SARP. Predicted temperatures show significant margin to material failure (as described in the SARP). The SARP states that at -40°C ambient temperature, no material would be affected, including O-rings.
3.7 Thermal Evaluation Under Hypothetical Accident Conditions The calculation approach described in the SARP assumes the PUSC and its contents can be represented as one node model with the surface area equal to the external surface of the PUSC and an effective mass selected to maximize temperatures of interest. The approach uses HAC regulatory requirements for the container to be exposed to a radiative fire with an emissivity of at least 0.9 at a temperature of 1475°F for a period of 30 mins following the free drop and puncture accidents. Initial conditions are taken for the NCT analysis. The approach maximizes the temperature rise of the container. The fire heat flux is analytically calculated and used to obtain the temperature rise of the container and its contents. The temperature rise of the container during HAC will result in damage to the pressure seals and, therefore, the container will not maintain the initial container internal pressure. Predicted temperature will not challenge the integrity of the container and its content.
17
3.8 Evaluation Findings
Based on review of the statements and representations in the application, the staff concludes that the thermal design has been adequately described and evaluated, and that the thermal performance of the PUSC package and its content meet the thermal requirements in 10 CFR Part 71.
4.0 CONTAINMENT EVALUATION The objective of this review is to verify that the containment boundary associated with the S-6213 PUSC Model 3, which is used to transport unirradiated S1B power units, is adequately described and evaluated under NCT and HAC to meet the 10 CFR Part 71 regulations.
Regulations applicable to the containment review include 10 CFR 71.31, 71.33, 71.35, 71.43, and 71.51. The application included an initial SARP that added the S1B power unit to the S-6213 PUSC (e.g., the allowance of an additional material selection for PUSC fabrication); S-6213 PUSC Model 1 and Model 2 were previously reviewed by staff.
According to the SARPs containment chapter, the containment boundary consisted of the cladding material surrounding the fuel; the new cladding material of the unirradiated S1B power units fuel was considered in the materials section of this SER. The SARPs containment chapter also indicated that the fuel design and fabrication inspections (e.g., dimensional inspection, ultrasonic and radiographic inspections) are consistent with previous Naval fuels and that monitoring of Naval fuels during reactor operations has not shown evidence of cladding failure. The fuel and its cladding during transport are confined by both the S1B power unit and the S-6213 container.
In order to support 10 CFR 71.43, the SARPs structural chapter discussed the features that ensure the fuel content is securely enclosed within the PUSC and cannot be opened unintentionally or by a pressure that may arise in the package. The SARPs containment chapter and structural chapter indicated that 10 CFR 71.51(a)(1) was met because the NCT tests did not affect the containment boundary and, therefore, there would be no release of content. Similarly, 10 CFR 71.51(a)(2) was met because the HAC tests showed that cladding stresses were below cladding yield strength such that there is no reduction in containment boundary effectiveness. In addition, the SARPs thermal chapter indicated that cladding temperatures during NCT and HAC tests did not approach maximum allowable cladding temperatures and, therefore, there would be no breach of the containment boundary.
Although the S-6213 PUSC is not the containment boundary, the SARPs package operations chapter and the SARPs acceptance test chapter indicated that the S-6213 PUSC is pressurized and leak tested (i.e., monitoring of pressure) and that corrective measures and repairs would be performed if pressurized acceptance criteria were not met.
4.1 Evaluation Findings
F4.1 The staff has reviewed the applicants description and evaluation of the containment system and concludes that the package includes a containment system securely closed by a positive fastening device that cannot be opened unintentionally or by a pressure that may arise within the package.
F4.2 The staff has reviewed the applicants evaluation of the containment system under normal conditions of transport and concludes that the package is designed, constructed,
18 and prepared for shipment so that under the tests specified in 10 CFR 71.71, Normal Conditions of Transport, the package satisfies the containment requirements of 10 CFR 71.43(f) and 10 CFR 71.51(a)(1) for normal conditions of transport with no dependence on filters or a mechanical cooling system.
F4.3 The staff has reviewed the applicants evaluation of the containment system under hypothetical accident conditions and concludes that the package satisfies the containment requirements of 10 CFR 71.51(a)(2) for hypothetical accident conditions, with no dependence on filters or a mechanical cooling system.
Based on review of the statements and representations in the application, the staff concludes that the package has been adequately described and evaluated to demonstrate that it satisfies the containment requirements of 10 CFR Part 71.
5.0 SHIELDING EVALUATION The objective of this shielding evaluation is to ensure that this package, as it pertains to shielding, protects immediate area workers and members of the public against radiation that is above the regulatory limits stated in 10 CFR Part 20, 10 CFR Part 71, and 10 CFR Part 173.
The applicant requested a review from the NRC technical staff for this package. For this review, the staff finds the package, including transport vehicles, satisfactorily meets the requirements of 10 CFR Part 20, 10 CFR Part 71, and 10 CFR Part 173. The staff also verified the information provided by the applicant is consistent with above mentioned regulations.
5.1 Evaluation Findings
The staff reviewed and evaluated the applicants statements and representations in the application. Based on the above, the staff concludes that the technical specifications sufficiently minimize dose to any immediate area workers and any real individual to the public and meet the regulatory requirements of 10 CFR Part 71.
6.0 CRITICALITY The staff reviewed the criticality safety evaluation of the S-6213 PUSC when loaded with an S1B power unit. The S-6213 PUSC is used to transport a single S1B power unit.
The applicant evaluated the S-6213 package loaded with an S1B power unit using conservative and optimum conditions that maximized the reactivity of the package using an approved three-dimensional Monte Carlo methodology. The applicant described the significant reactivity control features of the package. NCT and HAC were evaluated for a single package and arrays of packages and demonstrated that the calculated keff to be below 0.95 in all instances which is in compliance with the regulations of 10 CFR Part 71. The calculated Criticality Safety Index of the S-6213 package was confirmed to be 100 for the loaded package.
6.1 Evaluation Findings
The staff reviewed and evaluated the applicants statements and representations in the application. The staff evaluated the criticality calculation methodology, computer code utilized, the cross-sectional data sets used, as well as the conservativisms used to maximize the reactivity of the packaged S1B power unit. Since the resulting keffs for the system under both
19 NCT and HAC were confirmed through the applicants analysis to be less than 0.95, the staff concludes that the S-6213 PUSC package containing an S1B power unit under the assumptions utilized by the applicant meets the criticality safety requirements of 10 CFR Part 71.
7.0 MATERIALS REVIEW The applicant submitted an application to ship new unirradiated S1B power units in the existing Model 2 and new Model 3 S-6213 PUSCs. The staff reviewed the SARP (Reference 1) for DOE-NR Certificate of Compliance (CoC) USA/9186/B(U)F-96 (DOE-NR) to verify that the material performance of the package meets the requirements of 10 CFR Part 71. The Model 2 PUSC has been previously approved for shipments of the S6W Advanced Fleet Reactor (AFR) and high performance fleet core (HPFC) power units (Reference 2), the S9G/Next Generation Reactor (NGR) power unit (Reference 3), and the S9G/Virginia Forward Fit (VAFF) power unit (References 3 and 4). Only the sections of the materials evaluation that differ from the previous SARP will be discussed below.
7.1 Materials of Construction As described in SARP section 1.2.1 and table 1.2-1, the Model 3 PUSC differs from the Model 2 in its materials of construction. Namely, the Model 3 PUSC uses high-strength low-alloy steel HSLA-100 for components that were previously fabricated from HY-80 in the Model 2 design.
Additionally, the Model 3 PUSC uses Cover Impact Limiter to Container Screws fabricated from ASTM B166 Alloy 600 nickel-chromium alloy vice the Type 304 stainless-steel used in the Model 2 design.
As described in SARP section 1.1, shipment of a S1B power unit in the S-6213 PUSC requires new adaptive hardware to mate with and improve handling of the S1B power unit. This adaptive hardware consists of a lifting and shipping ring (LASR) and a flange adapter. As described in SARP section 1.2.1.1.8 and drawing 111E8594, the LASR consists of two 180° ring forgings that are connected together with 4 torque bolts. The ring forgings are fabricated from ASTM A508/A508M, Grade 4N, Class 1 alloy steel. The torque bolts are fabricated from AISI 4340 alloy steel. As described in SARP section 1.2.1.1.9 and drawing 111E8782, the flange adapter consists of a ring fabricated from ASTM A508/A508M, Grade 4N, Class 1 alloy steel.
As described in SARP section 1.2.1.2 and drawing 11E3146, the S1B power unit uses similar materials of construction to previously approved power units with the addition of ASTM A372/372M alloy steel.
The staff reviewed the description of the materials of construction, as described in SARP section 1.2, for the Model 2 and 3 PUSCs and the S1B power unit and find it to be acceptable.
7.2 Drawings The applicant provided new drawings in appendix 1.3.3 of the SARP to incorporate the Model 3 PUSC and the S1B adaptive hardware. The drawings include a parts list that provides the material specification of each component, and the welding and examination requirements. The staff notes that the level of detail in the new drawings are consistent with those of the previously approved drawings. The staff reviewed the drawing content with respect to the guidance in NUREG-2216, Standard Review Plan for Transportation Packages for Spent Fuel and Radioactive Material, section 7.4.1, Drawings, and NUREG/CR-5502, Engineering Drawings for 10 CFR Part 71 Package Approvals. The staff confirmed that the drawings provide an
20 adequate description of the materials, fabrication, and examination requirements. Therefore, the staff finds the drawings to be acceptable.
7.3 Codes and Standards As described in SARP section 2.1.4 and the drawings in SARP appendix 1.3.3, the Model 3 PUSC and S1B adaptive hardware adopt the same military standards (including those of the Naval Nuclear Propulsion Program) and ASTM International codes and standards as the previously approved Model 2 PUSC. The staff notes the use of military and ASTM standards is consistent with the guidance in NUREG-2216 for important to safety components that do not comprise the containment boundary. Therefore, the staff finds the materials codes and standards to be acceptable.
7.4 Material Properties The staff reviewed the material properties provided in SARP table 2.2-2 and table 2.2-4 of chapter 2 and table 3.2-1 of chapter 3 and verified that the applicant did not make any changes to the mechanical and thermal properties used in the structural analyses and thermal analysis, except for the addition of properties for HSLA-100, ASTM B166, and ASTM A372/372M. The staff reviewed the mechanical and thermal properties provided for these new materials and verified that they are consistent with military handbook values, laboratory data, research literature and/or ASTM values.
The applicant, in SARP chapter 2, appendix 2.12.11, provided an evaluation of fracture toughness for the PUSC components and the S1B adaptive hardware. The staff reviewed this addendum and verified that appropriate testing was performed to ensure that the HSLA-100 PUSC components and ASTM 508/A508M adaptive hardware have sufficient fracture toughness in accordance with the Category III fracture toughness criteria in RG 7.11. As described in table 2.12.11-2 of appendix 2.12.11, ASTM B166 Alloy 600 does not exhibit ductile to brittle transition with decreasing temperature and is not susceptible to brittle fracture.
The staff reviewed the applicants thermal analysis to ensure that the material properties remain valid under the service conditions associated with the S1B power unit loaded into the PUSC. In SARP sections 3.3 and 3.4.3, the applicant evaluated the maximum temperatures of the shipping container and power unit under NCT and HAC. The staff reviewed the applicants analysis and verified that the component temperatures remain below each of the materials allowable service temperatures. As described in SARP section 3.4.3, the O-rings located near the outside of the PUSC, during the HAC fire test, will experience temperatures in excess of their maximum temperature limit provided in SARP section 3.2.1. Consequently, the O-rings may fail and result in loss of container internal pressure. The applicant stated that this condition is acceptable because maintenance of the PUSC internal pressure is not required for the package safety. The staff agrees with this assessment as the shipping container itself provides no containment function.
Per the above discussion, the staff finds the mechanical and thermal properties used in the applicants structural and thermal analysis to be acceptable.
7.5 Welding and Nondestructive Examination As described in SARP sections 2.1.4, 8.1.2, and drawing 1002N997, the Model 3 PUSC welding and fabrication requirements are in accordance with ASME B&PV Code,Section III, Division 3,
21 with the exceptions listed in section IV.A of drawing 1002N997. Welding procedures will be in accordance with ASME B&PV Code Section IX, with the additional requirements listed in section III.C of drawing 1002N997. Nondestructive examinations (NDE) of the welds will be in accordance with applicable Naval Sea Systems Command manuals and acceptance criteria per applicable military standards as described in section V of drawing 1002N997.
As described in SARP drawings 111E8782 and 185D6417, the S1B adaptive hardware uses the same codes/standards for welding design, fabrication, and examination as the previously approved Model 2 PUSC.
The staff reviewed the welding codes identified and determined that they are consistent with the guidance in NUREG-2216. Therefore, the staff finds the welding and NDE codes and standards to be acceptable.
7.6 Criticality Control The method of criticality control for the shipment of the S1B power unit in the S-6213 PUSC is internal to the package contents and is the same method previously evaluated and approved in the staffs prior review of the PUSC.
7.7 Corrosion Resistance and Content Reactions The staff reviewed the application and section 2.2.2 of the SARP and verified that they do not introduce any adverse corrosive or other reactions that were not previously considered in the staffs prior review of the PUSC. The materials of construction and the service environments are bounded by those that were previously evaluated and approved in the CoC. Therefore, the staff finds the applicants evaluation of corrosion resistance and potential adverse reactions to be acceptable.
7.8 Package Contents As described in SARP section 1.2.1.2 and drawing 111E3146, the S1B power unit consists of a core basket, fuel assemblies, control rod assemblies, and a closure head that sits on the core basket. As mentioned in section 7.4 of this SER, the S1B power unit uses similar materials of construction to previously approved power units with the addition of ASTM A372/372M alloy steel.
The fuel assemblies contain unirradiated fresh fuel, with the quantity of radionuclides and a description of the chemical and physical form in SARP sections 1.2.2.1 and 1.2.2.2 respectively.
As described in SARP section 4.1, the fuel cladding provides the containment boundary and the shipping container itself provides no containment function. The applicant provided material properties for S1B cladding materials in SARP chapter 2, table 2.2-4. The staff reviewed these cladding material properties and verified that they are consistent with military handbook values.
In SARP chapter 2, appendix 2.12.10, the applicant identified the components of the power unit that are susceptible to brittle fracture. The applicant evaluated whether the components have acceptable brittle fracture performance during NCT and HAC by ensuring the stress intensity factor for each test is less than the static fracture toughness for each susceptible component.
The staff reviewed the stress intensity factors and stress fracture toughness values in tables 2.12.10-11 and 2.12.10-12 and determined that all power unit components have acceptable brittle facture performance during NCT and HAC.
22 The applicant provided a thermal analysis in SARP sections 3.3 and 3.4 to evaluate the fuel performance during NCT and HAC. The staff reviewed this analysis and verified that adequate margin is provided to the maximum fuel temperatures that could result in fuel cladding rupture.
Per the above discussion, the staff finds that applicants description of the chemical and physical form of the package contents acceptable and the mechanical properties of the fuel modules are adequate to ensure that the fuel remains in the analyzed configuration under NCT and HAC.
7.9 References 1.
Department of Energy (DOE), NR:RR:JHKampen G#C24-02642, S-6213 Shipping Container - Safety Analysis Report for Packaging to Support Shipment of S1B Power Unit; Request for Nuclear Regulatory Commission Review and Concurrence, June 11, 2024.
2.
WAPD-REO(C)-1566 - S6W Shipboard Power Unit in Model 2 S6213 Power Unit Shipping Container Safety Analysis Report for Packaging, Rev. 4, Bettis Atomic Power Laboratory (Transmitted by WAPD-REO(C)-1929, September 30, 1992.
3.
RSS-SC-NFE-00025 - S9G Power Unit in the S-6213 Power Unit Shipping Container Safety Analysis Report for Packaging, Rev. 6.
4.
RSS-SC-NFE-00050 - S9G Power Unit in the S-6213 Power Unit Shipping Container Safety Analysis Report for Packaging Addendum, Rev. Original, Fluor Marine Propulsion, LLC for the DOE (Transmitted by RSS-SC-NFE-00075), December 15, 2022.
7.10 Evaluation Findings F7.1 The applicant has met the requirements in 10 CFR 71.33. The applicant described the materials used in the transportation package in sufficient detail to support the staffs evaluation.
F7.2 The applicant has met the requirements of 10 CFR 71.31(c). The applicant identified the applicable codes and standards for the design, fabrication, testing, and maintenance of the package and, in the absence of codes and standards, has adequately described controls for material qualification and fabrication.
F7.3 The applicant has met the requirements in 10 CFR 71.43(f) and 10 CFR 71.51(a). The applicant demonstrated effective materials performance of packaging components under normal conditions of transport and hypothetical accident conditions.
F7.4 The applicant has met the requirements of 10 CFR 71.43(d). The applicant has demonstrated that there will be no significant corrosion, chemical reactions, or radiation effects that could impair the effectiveness of the packaging.
F7.5 The applicant has met the requirements of 10 CFR 71.43(f) and 10 CFR 71.55(d)(2). The applicant has demonstrated that the package will be designed and constructed such that the analyzed geometric form of its contents will not be substantially altered, no loss or
23 dispersal of the contents, and no substantial reduction in the effectiveness of the packaging under the tests for normal conditions of transport.
The staff concludes that the SARP (Reference 1) adequately considers material properties and material quality controls such that the design is in compliance with 10 CFR Part 71. This finding is reached on the basis of a review that considered the regulation itself, appropriate regulatory guides, applicable codes and standards, and accepted engineering practices.
8.0 OPERATING PROCEDURES The staff reviewed the operating procedures for the package using the guidance in NUREG-2216 and found them to be adequate. Based on a review of the statements and representations in the application, the staff concludes that the operating procedures meet the requirements of 10 CFR Part 71 and that these procedures are adequate to assure the package will be operated in a manner consistent with its evaluation for approval.
9.0 ACCEPTANCE TESTS AND MAINTENANCE PROGRAM The staff reviewed the acceptance test and general maintenance program for the package using the guidance in NUREG-2216 and found them to be adequate. Based on a review of the statements and representations in the application, the staff concludes that the acceptance tests and maintenance program meet the requirements of 10 CFR Part 71 and that these tests and programs are adequate to assure that the package will be maintained in a manner consistent with its evaluation for approval.
CONDITIONS In addition to small editorial changes, the following changes have been made to the certificate:
Condition No. 3b has been revised to reflect a more simplified title for the SARP.
Condition No. 5(a) has been revised to include Model 3 of S-6213 PUSC as packaging and a description of Model 3.
Condition No. 5(b) has been revised to include S1B power unit as approved contents.
The references section has been updated to include this request.
CONCLUSIONS Based on the statements and representations contained in the application, and the conditions listed above, the staff concludes that the design has been adequately described and evaluated, and the Model No. S-6213 power unit shipping container package meets the requirements of 10 CFR Part 71.
Issued with CoC No. 9186, revision No. 21.